A group made up of dozens of cybersecurity experts, including several well-known veterans of the industry, published an open letter to the U.S. government asking it to lift the export control order on Anthropic’s Fable and Mythos models.

According to the open letter, “this action has taken the best models away from [cybersecurity] defenders” who now can’t use the models to find vulnerabilities and make their software and products more secure.

“To pull the best capabilities away from defenders without a good reason when our adversaries are rapidly advancing is dangerous,” read the letter.

On Friday, the U.S. government ordered Anthropic to limit the export of Fable and Mythos citing national security concerns, without explaining the specific reasons behind the order, according to Anthropic. In response, the company suspended access to the models to all users worldwide.

As of this writing, the letter is signed by 76 cybersecurity experts, including: former Facebook chief of security Alex Stamos; Casey Ellis, the founder bug bounty platform Bugcrowd; famed cryptographer and former Apple security design and architecture manager Jon Callas; computer scientist Paul Vixie; Dino Dai Zovi, the former head of applied security engineering at Block; Katie Mossouris, the founder of Luta Security; and Rachel Tobac, the CEO of the security awareness training firm SocialProof Security.